FIG. 5 shows a solar cell disclosed in Patent Literature 1. This solar cell comprises a reverse electrode layer 4, an n-type GaAs layer 1, a p-type GaAs layer 2, and an obverse electrode 3. An example of a material of the obverse electrode 3 is gold, silver, or platinum. A window layer 5 and an anti-reflection film 6 are provided around the obverse electrode 3.
The irradiation of sunlight to the obverse electrode 3 reduces efficiency of the solar cell, because the light arrived at the obverse electrode 3 is reflected on the obverse electrode 3 and fails to be led to the p-type GaAs layer 2.
In order to solve this problem, this solar cell comprises a cover glass 7 having a convex part 7a. In the cross-sectional view, the obverse electrode 3 is located under the convex part 7a. The convex part 7a allows the sunlight which travels toward the obverse electrode 3 to be refracted and to be led through the anti-reflection film 6 and the window layer 5 to the p-type GaAs layer 2.